Manufacture of hydrocarbon gases from coal



Patented Aug. 6, 1940 J i I .YJIU-MTED'ST TES rariEN-rporrlce f1 'No Drawing. "Application JuneZ-Z, 1937, Serial a No. 149,663. In Great BritainfJuly--23,'1936 1 Glaimsiiir fiwfil -'This invention relates to the'manufacture of advantage' to' employ higher temperatures in the hydrocarbon gases from coal. later-stages-oftheextraction process than in the Reactive hydrocarbon gases; such for example earlier; -for *example the extraction may be com as acetylene and the lower olefines, e.'g. ethylene menced at atemperature of about 250-280 C.- and propylene, are of considerable value as raw while in the'flater stages-temperatures of 300 5 materials in the manufacture of aliphatic and to 330 or-350 C. and higher may be used. Pref other chemicals. For example ethylene may be erably' theextraction is carried out at'a temperaemployed in the manufacture of ethyl alcohol ture only slightly below the decomposition temor diethyl ether by absorption in sulphuric acid peraturegof'theparticular coal being treated, I 10' and subsequent hydrolysis of the absorption and asthe'extra'ctionproceeds and the decompo- 10 product. Acetylene may be converted into acetsition temperature of the residue rises, the tem-' aldehyde by hydration in the presence of various perature-of the'extracting solvent may be raised catalysts, for example mercury salts, and acetcorrespondingly. The pressure may be atmosaldehyde is a useful raw material for theproducpheric or sufiicient to maintain thesolvent in the tion of acetic acid. It is thus apparent that if liquid phase, but higher pressures are preferably 15 these reactive hydrocarbons can be produced in used, fofinstance pressures up to*10, 20, 50, 100 high yields by a relatively simple and inexpensive orl) atmospheres: Such pressures may for exp-rocess' from coal, this will provide not only a ample be producedbymeans of hydrogen orvery convenient source of the aliphatic and other other gas; 20 chemicals but also'a valuable method of utilising The extraction may be carried to any desired 2 coal. a a staga jEFOr example it may be carried substan.

According to the present invention coal is subtially to q ip t r iIrW ase 'Or more jected to extraction with an organic solvent or of the matter contained in the coal may be ex solvent mixture, the extracted fraction of the trac'tedfor it may be stopped at some earlier coal is hydrogenated, and the product is subjected stage, for instance when 50 or 60% of the coal 25, to thermal decomposition. has been extracted. I [The extraction may be performed with the aid Before subjecting the extracted fraction of the of a great variety of organic solvents. For 'ex- Goal tofhydrogenation, it is advisable'to add ample hydrocarbons or other neutral solvents thereto faflhydrogenation catalyst, for example m'ay' bemplbyed, e. g. tetrahydronaphthalene or .stannous hydr i oxalate, 'm y d a dso decahydronaplithalenebr higher boiling hydroor'ammonium molybdate, or, especially when the carbons,"ior example phenanthrene, hydrogen: extract contains little sulphur, nickel. Either ate'd .anthracenes andphenanthrenes, benzylbefore orpre e bly after the addition of the naphthalenes, diphenyl benzene 'and'tetra-amyl-J catalyst, the extracting solvent'may if desired ene. well 'as, or instead of, neutral solventsj be partly or wholly m fi example y 35 there maybe used phenols, for example relatillationon in some other suitable way, 'tively highboiling fractions of tar acidsor more 'Il'leehydro gnation may be carried out under or less cliemicallypure phenols, such as p-benz'yl e mbsp eric' p ess for ple, p es phenol or l-[a-'-'hydroxy-be nzyl]' naphthalene, or. s e of 00 0 p e b it s found 40 basic compounds may be used, for"instance pyri-' possible to cause hydrogen to combine with the 4 dine, quinoline, "quinaldine, or "higher boilingf xt a at c i w r p e u es, e. basesfe. g; acridine, benzyl quinolines, hydro-f p fi 'es offill o'rfl2fl atmosp eres. The hy genated acridines' and other hydrogenated hetereriatioh step may j desired-be p d in ocyclicbases. Advantageously a neutral solvent 1 to Produce .oils of lower boiling P011117 a maybe employed in association with a phenol h se produced in the first sta 5 or a basic solvent: For example a hydrogenated T Oi s p 0duce d bythe hydrogenation of naphthalene may be used in association with the extract arethen converted into reactive hy phenols, the phenols being present for instance d bQ f sfl by thermal mp t in amount b-etween 15--and 35%, or with basic Pre a y h o r vaporised d su je t d compounds which may be present in similar to decomposition while in the vapour phase, at 50 amounts or in smaller quantities. a temperatures above about250? or;300 C., for ex-- v,The temperature atwhich the extraction is ample emp r sof 00- 0 C. 01 more. carried outmay-be above 200 or 250 0.; for in--,. ,Io,,-pr.oduce considerable amounts of olefines stance temperatures between about 300 and' the vaporised oilsmay be heated in a turbulent 5e. 7.99-3-,Q..:a 1enart q ar yva uable. is. t no treamohetr ene 7 nd 90050., nd e pe:

cially between 800 and 900 C., while to produce acetylene temperatures above 1000 C., especially 1150 to 1200 C., may be used. If desired the temperature may rise either continuously or in stages as the' thermal decomposition proceeds towards completion, and this tends to increase the yield of olefinic or acetylenic gases as opposed to methane and hydrogen. The pressure under which the decomposition is conducted may be, for example, atmospheric or higher than atmospheric, for example 10 to 20 atmospheres, but particularly good results are obtained by employing pressures less than atmospheric, e. g. down to 6 or atmosphere or less. It is advisable to cool the products of the decomposition rapidly as soon as they leave the decompositionzone.

The gases and vapours produced in this stage may be separated, at least to some extent, from one another. For example they may first be cooled so as to condense higher boiling constituents, for example light oils and the like, which may, after beingv suitably refined, be used as motor fuels or for other purposes. On the other hand, if desired, they may be further treated to produce reactive hydrocarbon-gases. Advantageously they may be vaporised and passed in a turbulent stream through a tube at a temperature of, for example, between about 600 and 1000 C. or 1400 C. in order to produce olefines or acetylene. If desired the light oils and similar constituents produced in the thermal decomposition may be hydrogenated before use or before being converted into other substances.

From the gases remaining after the removal of i the less volatile constituents unsaturated hydroconsists largely of methane and may, for instance,

carbons may, with advantage, be removed. For example the gases may be passed over charcoal in such a way as to absorb olefines on the charcoal, or other agents may be employed, for instance concentrated sulphuric acid. The gas remaining be employed in the manufacture of acetylene by thermal decomposition. Hydrogen contained in the gas, and hydrogen obtained as a by-product in the thermal decomposition of the methane,

similar constituents have been condensed may, without further separation, be subjectedto pyrolysis to produce acetylene.

The following example illustrates, but does not in any way limit, the invention.

Example Bituminous coal of high volatile content is powdered and extracted with a mixture comprising parts by weight of decahydronaphthalene or a mixture of hydrogenated naphthalenes and 10 parts of pyridine, under a pressure of 50-70 atmospheres. The temperature at the beginning of the extraction is 260 C., and this is slowly raised to about 350 C. as the treatment proceeds. When the extraction is substantially complete,

the solution is run off from the undissolved residue of the coal, and the pressure is reduced so that the pyridine and the greater part of the hydrogenated naphthalene distils off. The extracted fraction, together with the remainder of the extracting solvent and a molybdenum catalyst which has previously been heated to 500 C. in air, is subjected to a hydrogen pressure of about atmospheres at a temperature of 450-500 C. The products of the hydrogenation are vaporised under a pressure of 100 mm., and passed rapidly through narrow tubes heated to 850 C., and on issuing from the tubes the gaseous products are rapidly cooled. The olefines formed may be separated by absorption on charcoal.

Having described my invention what I desire to secure by Letters Patent is:

1. Process for the manufacture of unsaturated gases from coal, which comprises heating coal to a temperature between 200 and 400 C. under a pressure higher than 10 atmospheres with an organic solvent composition capable of extracting part of the coal by solution, separating the extract from the residue of the coal, subjecting the extract to hydrogenation under a pressure of at least 20 atmospheres in the presence of a hydrogenation catalyst, vaporizing the product of the hydrogenation, subjecting said product, at a vapor pressure less than atmospheric, to a temperature exceeding 400 C., and rapidly cooling the gases so formed.

2. Process for the manufacture of unsaturated gases from coal, which comprises heating coal to a temperature between 200 and 400 C. under a pressure higher than 10 atmospheres with an organic solvent composition capable of extracting part of the coal by solution, separating the extract from the residue of the coal, removing at least part of the solvent composition by distillation, subjecting the extract remaining to hydrogenation under a pressure of at least 20 atmospheres in the presence of a hydrogenation catalyst, vaporizing the product of the hydrogenation, subjecting said product, at a vapor pressure less than atmospheric, to a temperature exceeding 400 C., and rapidly cooling the gases so formed.

3. Process for the manufacture of gaseous olefines from coal, which comprises heating coal to a temperature between 200 and 400 C. under a pressure higher than 10 atmospheres with an organic solvent composition capable of extracting part of the coal by solution, separating the extract from the residue of the coal, subjecting the extract to hydrogenation under a pressure of at least 20 atmospheres in the presence of a hydrogenation catalyst, vaporizing the product of the hydrogenation, subjecting said product, at a vapor pressure less than atmospheric, to a temperature between 700 and 900 C., and rapidly cooling the gases so formed.

4. Process for the manufacture of acetylene from coal, which comprises heating coal to a temperature between 200 and 400 C. under a pressure higher than 10 atmospheres with an organic solvent composition capable of extracting part of the coal by solution, separating the extract from the residue of the coal, subjecting the extract to hydrogenation under a pressure of at least 20 atmospheres in the presence of a hydrogenation catalyst, vaporizing the product of the hydrogenation, subjecting said product, at a vapor pressure less than atmospheric, to a temperature between 1000 and 1200 C., and rapidly cooling the gases so formed.

5. Process for the manufacture of gaseous olefines from coal, which comprises heating coal to a temperature between 200 and 400 C. under a pressure higher than 10 atmospheres with a hydrogenated naphthalene containing 15 to 35% of a phenol until at least 50% of the coal has gone into solution, separating the solution from the residue of the coal, removing the phenol and at least part of the hydrogenated naphthalene by distillation, subjecting the solution remaining to hydrogenation under a pressure of at least 20 atmospheres at a temperature between 450 and 500 C. in the presence of a hydrogenation catalyst, vaporizing the product of the hydrogenation, subjecting said product, at a vapor pressure less than atmospheric, to a temperature between 700 and 900 0., and rapidly cooling the gases so formed.

6. Process for the manufacture of acetylene from coal, which comprises heating coal to a' temperature between 200 and 400 C. under a pressure higher than atmospheres with a hydrogenated naphthalene containing to 35% of a phenol until at least 50% of the coal has gone into solution, separating the solution from the residue of the coal, removing the phenol and at least part of the hydrogenated naphthalene by distillation, subjecting the solution remaining to hydrogenation under a pressure of at least atmospheres at a temperature between 450 and 500 C. in the presence of a hydrogenation catalyst, vaporizing the product of the hydrogenation, subjecting said product, at a vapor pressure less than atmospheric, to a temperature between 1000 and 1200 0., and rapidly cooling the gases so formed.

7. Process for the manufacture of gaseous olefines from coal, which comprises heating coal to a temperature between 200 and 400 C. under a pressure higher than 10 atmospheres with a hydrogenated naphthalene containing 15 to of pyridine until at least of the coal has gone into solution, separating the solution from the residue of the coal, removing the pyridine and part of the hydrogenated naphthalene by distillation, subjecting the solution remaining to hydrogenation under a pressure of at least 20 atmospheres at atemperature between 450 and 500 C. in the presence of a hydrogenation catalyst, subjecting said product, at a vapor pressure less than atmospheric, to a temperature between 700" and 900 C., and rapidly cooling the gases so formed.

HENRY DREYFUS. 

